Don't you get it? It's supposed to be a "big mystery"! Is Ben Solo the "Skywalker" that is rising, or is it Rey?!
You see, Kylo Ben told Rey that her parents were nobodies, right? But we all know that in this "brave new world" of SW that the things people say don't really
mean anything, they're just having some convos to kill the time between those sweet lightsaber fights and dumb bitches running around in purple hair blowing up star destroyers with hyperdrives, amirite?!?!?!
So, it's a pointless title with a pointless mystery intended to draw you to the theater one last time for a raping of your wallet, eyeballs, and brain matter.
And a dumbassed Emperor laugh at the end. Maybe HE'S the "rising Skywalker"!!!!
Or, or, maybe it's the force ghost of Anakin finally! The Ghost of Anakin Rises!
Or, maybe it's the Jedi themselves! Maybe Luke's force ghost comes back with Anakin's force ghost and they help Rey defeat Kylo and start a NEW JEDI ORDER!!!!
OH! THE POSSIBILITIES!!!!